C15H24O 220.35

Phenol,2,6-bis(1,1-dimethylethyl)-4-methyl-.
2,6-Di-tert-butyl-p-cresol [128-37-0].

Packaging and storage— Preserve in well-closed containers.

Identification— To 10mLof a solution in methanol (1in 100,000)add 10mLof water,2mLof sodium nitrite solution (3in 1000),and 5mLof dianisidine dihydrochloride solution (1in 500),prepared by dissolving 200mg of dianisidine dihydrochloride in a mixture of 40mLof methanol and 60mLof 1Nhydrochloric acid:an orange-red color develops within 3minutes.Add 5mLof chloroform,and shake:the chloroform layer exhibits a purple or magenta color,which fades when exposed to light.

Congealing temperature á651ñ: not lower than 69.2,corresponding to not less than 99.0%of C15H24O.

Residue on ignition á281ñ— Transfer about 50g,accurately weighed,to a tared crucible,ignite until thoroughly charred,and cool.Moisten the ash with 1mLof sulfuric acid,and complete the ignition by heating at 800±25for 15-minute periods to constant weight:the limit is 0.002%.

Heavy metals,Method IIá231ñ: 0.001%.

Organic volatile impurities,Method IVá467ñ: meets the requirements.[NOTE—A G16column has been shown to be an appropriate secondary column.]

Expert Committee:(EMC)Excipients:Monograph Content

USP28–NF23Page 2968

Phone Number:1-301-816-8262